08 yz250f wont start after sitting up

Paul W

• 404 Answers
• Posted on Feb 06, 2009

SOURCE: yz 250 wont kickstart

Hi!
You obviously look after your machine and very sensible when laying up, however as you are probably aware 2 strokes rely heavily on compression, A. to produce excellent combustion and B. to draw fuel into the chamber. So when you try kick starting you can't get enough revolutions to draw the correct amount of fuel into the cylinder, where as you push start you constantly turn over the engine increasing compression slightly and bingo it fires.
Can you remember how when kick starting it before this problem the feel on resistance when kicking over? has it now become a lot easier? if so you possibly have worn or broken compression piston rings.
A compression test will reveal this, I hope this sorts your query?
Press the Blue button please for my FREE effort,
Thank You!
Paul 'W' U.K.

SOURCE: while riding my yz 125 it just died and won,t kick up again

• If a hole in the piston then install new piston and rings. Next, clean the carbon off the head and install a new head gasket.
• If cylinder wall is scared the piston has seized up. Pull the cylinder off and take it to the dealer. Have them bore the cylinder and return it along with a new oversize piston and rings.
• While at the parts counter, get a new stock spark plug and a supply of Yamalube Two Stroke Motor Oil. You need to add 4 ounces per gallon when filling up. This will be a 32/1 gas to oil ratio. NEVER ride the bike without at least the needed 32/1 mix.

SOURCE: my 01 yz 125 wont start with kick start,n loses power in low rpms

sounds if you picked up some water/dirt in fuel when was low

clean fuel bowl and flush carb by drain port if still ruff then remove carb for cleaning

SOURCE: My Yamaha yz250F 07 starts first kick but back

I see: you changed the plug because it was backfiring.

Does it back fire when you let OFF the throttle after revving it, or does it back fire while being revved?

If it does it when you let off then Ollie's suggeston might do it. If that doesn't do it then check for dirt in your pilot jet.

If it back fires when revved up high could be dirt in your main jet.

SOURCE: Kick Start wont engage

check pawl spring on kickstart lever.